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COD LONG LAT PEAK BASE

1 11,28379 38,13380 120-130 380-390
2 10,63515 37,45867 50-60 190-200
3 10,79897 37,60927 80-90 200-210
4 11,25078 37,35827 300-310
5 11,46744 37,41904 120-130 240-250
6 11,33269 37,06234 50-60 210-220
7 11,55108 37,04971 60-70 400-410
8 11,73529 37,03383 400-410
9 12,69831 36,50845 130-140 950-960
10 12,58326 36,31815 230-240 760-770
710-720
550-560

Table 2: List of the unnamed structures such as seamounts, submarine volcanoes, banks and other
sea floor features in the Sicily Channel. The geographic coordinates have been estimated on the basis
of the EMODnet bathymetry map, with 10 m depth interval at 450 m horizontal grid. The first column
shows the codes reported in the figure 2 (red dots).

2.1.2 Deep sea seeps, mud volcanoes and pockmarks

Hydrothermal vents, mud volcanoes and pockmarks are extreme environments characterized
by different geochemical features and structural spatial complexity that can favour the
presence of several sub-habitats within a single deep-sea seep. The heterogeneity, spatial
complexity and variability of these structures play a role of the in time on maintaining the
diversity and functioning of the deep benthic community.

On the Malta plateau (or Hyblean-Malta plateau) Savini et al. (2009) discovered by detailed
acoustic mapping more than 100 small-scale domes and peculiar ridges were a few miles
offshore between 140 and 170 m water depth. The investigated seafloor features have been
interpreted as mud volcanoes and revealed different morphologies, in particular they are few
meter high (no more than 10m) and are arranged on the seafloor in two main different styles:

1) several conical features of 50 - 200m in diameter, preferentially aligned along the isobaths

2) numerous close-set small cones up to 10m in diameter heavily colonized by gorgonians
and appearing in video observation as carbonate structures, which are settled within well
defined, flat, elongated areas (the largest one reaches 2000m in its long axis and 500m in its
short axis) rising up to 10m form the seafloor.

Sea floor pockmarks are formed by gas discharge. They are features biologically relevant

due the possible existence of unique chemosynthesis-based communities in the cold seep
that are frequently found on them. Taviani et al. (2013) described a pockmark field located at

ca. −800 m in the Sicilian Channel, at the West of the Gela Basin (the basin between

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